Table 3. Multivariable-Adjusted Risk of Incident CVD by Smoking Status and Years Since Quitting: Never Smokers and Ever Smokers With at Least 20 Pack-Yearsa.
| Years Since Quitting | Person-Examinations, No. | Incident CVD Cases, No. | Person-Years, No. | Incidence Rate Per 1000 Person-Years (95% CI) | Former vs Current Smokers | Former vs Never Smokers | ||
|---|---|---|---|---|---|---|---|---|
| Hazard Ratio (95% CI) | P Value | Hazard Ratio (95% CI) | P Value | |||||
| Pooled Cohort | ||||||||
| Current smokers | 13 885 | 558 | 41 725 | 11.56 (10.30-12.98) | 1 [Reference] | |||
| <5 | 2586 | 101 | 7851 | 6.94 (5.61-8.59) | 0.61 (0.49-0.76) | <.001 | 1.40 (1.12-1.73) | .002 |
| 5 to <10 | 2088 | 99 | 6342 | 7.04 (5.66-8.76) | 0.61 (0.49-0.77) | <.001 | 1.42 (1.15-1.77) | .001 |
| 10 to <15 | 1429 | 76 | 4455 | 6.31 (4.93-8.09) | 0.54 (0.42-0.70) | <.001 | 1.25 (0.98-1.60) | .08 |
| 15 to <25 | 2123 | 145 | 6741 | 6.11 (5.01-7.44) | 0.55 (0.45-0.68) | <.001 | 1.22 (1.00-1.47) | .045 |
| ≥25 | 1326 | 116 | 4187 | 5.02 (4.00-6.31) | 0.45 (0.35-0.58) | <.001 | 0.98 (0.78-1.22) | .85 |
| Never smokers | 29 089 | 895 | 91 227 | 5.09 (4.52-5.74) | 1 [Reference] | |||
| Original Cohort | ||||||||
| Current smokers | 9727 | 363 | 20 450 | 13.04 (11.21-15.18) | 1 [Reference] | |||
| <5 | 1711 | 70 | 3613 | 8.62 (6.63-11.20) | 0.68 (0.52-0.88) | .004 | 1.31 (1.01-1.70) | .04 |
| 5 to <10 | 1268 | 63 | 2623 | 8.39 (6.35-11.07) | 0.66 (0.49-0.87) | .004 | 1.28 (0.97-1.69) | .08 |
| 10 to <15 | 850 | 44 | 1757 | 7.45 (5.37-10.32) | 0.59 (0.42-0.83) | .002 | 1.11 (0.80-1.53) | .54 |
| 15 to <25 | 1128 | 63 | 2361 | 5.65 (4.24-7.53) | 0.49 (0.36-0.66) | <.001 | 0.86 (0.65-1.14) | .29 |
| ≥25 | 670 | 62 | 1378 | 5.97 (4.39-8.11) | 0.50 (0.35-0.73) | <.001 | 0.90 (0.66-1.22) | .49 |
| Never smokers | 18 862 | 663 | 39 521 | 6.72 (5.77-7.82) | 1 [Reference] | |||
| Offspring Cohort | ||||||||
| Current smokers | 4158 | 195 | 21 275 | 7.71 (6.27-9.48) | 1 [Reference] | |||
| <5 | 875 | 31 | 4239 | 3.83 (2.59-5.65) | 0.51 (0.34-0.75) | <.001 | 1.51 (1.02-2.25) | .04 |
| 5 to <10 | 820 | 36 | 3720 | 4.29 (2.97-6.18) | 0.57 (0.40-0.82) | .002 | 1.68 (1.17-2.41) | .005 |
| 10 to <15 | 579 | 32 | 2698 | 3.86 (2.61-5.72) | 0.50 (0.34-0.74) | <.001 | 1.48 (1.01-2.17) | .046 |
| 15 to <25 | 995 | 82 | 4379 | 4.70 (3.52-6.29) | 0.62 (0.46-0.83) | .002 | 1.78 (1.36-2.33) | <.001 |
| ≥25 | 656 | 54 | 2809 | 3.00 (2.10-4.28) | 0.41 (0.28-0.60) | <.001 | 1.10 (0.79-1.54) | .57 |
| Never smokers | 10 227 | 232 | 51 706 | 2.57 (2.07-3.20) | 1 [Reference] | |||
Abbreviation: CVD, cardiovascular disease.
a
This analysis is limited to never and ever heavy smokers with at least 20 cumulative pack-years. Incidence rates and hazard ratios are adjusted for age, sex, education, examination decade, systolic blood pressure, antihypertensive medication, diabetes mellitus, body mass index, total cholesterol, and alcohol consumption. All dynamic variables are time-updated.